The prior art is already aware of machines such as tractors and cranes and the like which utilize an operator compartment or a cab which is rotatable about an upright axis on a support structure such as the tractor itself. One such example of a prior art crane is found in U.S. Pat. No. 3,909,961, and that has a cab which rotates about an upright axis and thus permits the operator and the working implement to face in any selected direction around an arc of rotation. The problem and concern with this type of arrangement is to heat the interior of the cab, and in some instances the heater for the prior art cabs has been a separate type of heater of a fuel-fired type which is made available to the interior of the cab. This type of heater is inherently dangerous and has both flame and fuel odors which are obnoxious as well as dangerous.
In the present invention, the heater utilizes the heat from the tractor engine itself and conducts that heat to the interior of the cab by a specially arranged enclosed space intervening between the support structure and the cab itself. Further, a present invention provides the arrangement as aforesaid and such that any rotated or turned position of the cab relative to the support structure will not cut off or even impede the flow of heated air into the cab though the air is flowing between the support structure and the rotatable cab itself. Still further the present invention accomplishes the aforementioned advantages and does so with inexpensive but reliable parts and arrangements and without in any way altering the basic construction of the support structure and the cab itself and thus without requiring any excessive space or complicated and expensive elements to achieve conducting the flow of heated air from the tractor engine and to the interior of the cab. Further, with this arrangement, the already available heat produced by the tractor engine is thus utilized, rather than being wasted, and is introduced into the interior of the cab for heating the cab.
Other advantages and objects will become apparent upon read- the following description in light of the accompanying drawings.